Halfway through my conversation with the playwright Richard Bean, he cries: "The great shame of modern society is that food has lost its spirituality." And I think, "Here comes the predictable Hugh-Fearnley-Whittingstall bit about the need to revive nettle-eating and Cornish rabbit-intestine stew recipes," and let myself drift off.

But this is Richard Bean, so I don't, in fact, get an invocation of peasants and pastures past. Instead, he jabs a finger out of the window of our upstairs room in the Royal Court Theatre in London and barks: "Look at all those people! There are what, 10 million people in this city? And they have all been fed!" (When he is "going off on one", as he so often is, all his sentences end with a question mark or an exclamation mark. In a way, this is the basis of his approach to writing.) "Who the fuck did that?" he goes on. "It's a miracle! And we take it for granted! And because we take it for granted, we treat the people who provide us with our food with contempt, when we should laud and value them."

As is clear from his earlier plays, such as Toast (set in a bread factory) and Under the Whaleback (about trawlermen in his native Hull), Bean is very good at lauding people without resorting to patronising, sentimental eulogies. His plays succeed because he presents his subjects' worlds and points of view unedited, in the raw. You wouldn't necessarily want the characters around for tea, but you do feel as if you have been shown something authentic and true.

In his new play, Harvest, Bean traces a story of British agriculture - specifically, pig farming - through four generations of a family farming on the East Yorkshire Wolds. This is of particular interest to me because, first, I grew up on a pig farm in the area and, second, in farming families there is an unspoken rule that you have to criticise any artistic depiction of farming life as being sentimental and inauthentic. I grew up thinking everyone sat in front of Emmerdale Farm observing that the milking parlours were unusually clean, or that tractor X would never, in reality, have sufficient horsepower to pull load Y. It is an annoying habit, but I am not entirely free of it, and so I came to Harvest ready to pick it apart.

But I couldn't. This might sound as if I am sucking up to my inter-viewee, but Harvest is as credible a depiction of modern farming life as you will see this side of a pigsty wall.

For a start, its historical scope and honesty mean you get a sense of rural life that is not the usual outside-perspective stuff of apple-cheeked feudalism and unchanging rhythms. Instead you see rather eccentric people struggling with the earth, the weather, animals, politics and each other, amid ongoing social and technological change. Squires are mocked and challenged. The bloke in charge of the pigs has a drink problem, and uses a harness designed to get sperm from boars for his own pleasures. A young woman from Hull comes to help, marries a German prisoner-of-war, and ends up running the farm with him. These are the kinds of stories I recognise (well, mostly - we didn't have a boar harness), about the sort of events that give life on small, old-fashioned farms the rough, cheery anarchy that makes them attractive.

Some commentators - the makers of the 1999 documentary Green and Pleasant Land, for instance - cite such coarse details to "explode myths" about rural life, but this misses the point. Those bucolic myths were mostly generated by urban artists, packaging designers and property speculators in the early years of the industrial revolution, exploiting the nostalgia and folk memory of an ex-rural working class that had moved to cities for work. Born-and-bred country people do love their environment, history and way of living, but they do not as a rule idealise it; that is the preserve of pressure groups and the National Farmers' Union.

Bean knows all this because his family belongs to the mixed-up version of country life. His father was born in an East Yorkshire village, trained as a blacksmith, and moved to Hull to become a policemen in the 1950s. He still kept a few pigs as a sideline, though, and 20 years later he retired to resume smithing and get a few more animals on a converted farm in North Yorkshire. Bean may be "100% Hull", but the family album contains photographs of him riding pigs as a small boy.

His half-uncle, on whose experience much of Harvest is based, had a pig farm that, like my family's and hundreds of others in Britain, went bust in the 1990s. This was chiefly because of the strong pound, and cheap imports from some European countries, where production costs were lower because governments had not enforced new EU welfare regulations as Britain - rightly - had. Pig farms, like their poultry counterparts, attract no subsidies, and so are exposed to markets skewed by now notorious EU mismanagement.

Bean had spent childhood summers on the farm, and at five ran away from school to try to go back, because he decided he wanted to work there. Whereas his uncle remained resigned about losing his house and livelihood, the playwright feels a sense of anger and loss all the more personally. "They just get on with life," he says. "It's people like me and you who see the tragedy in it."

Of course, many people in Bean's potential audience will have reservations about being asked to sympathise with British farmers, for various reasons. The intensive side of their industry has damaged the environ-ment. They still receive large subsidies, even though other industries have had to do without them. Through the 1970s and 80s their representatives were often arrogant and complacent about public criticism. They kill cute animals. They use man-made chemicals. They are perceived as being unprogressive, anti-European and, you know, a bit nasty.

Having lived among all this, I have always felt there are counter-arguments. Unfortunately, these tend to be complicated and boring: you can see people's eyelids droop when you try to explain that the Common Agricultural Policy actually damages British farms and food, or that (wake up!) objecting to the EU as an institution does not make you a little Englander. Bean, however, has all these arguments and more in Harvest, and it will be interesting to see how Royal Court audiences react to criticism of the EU, the pro-foxhunting sentiment and Bean's unfashionable reminder that intensive food production was introduced, with government encouragement, to feed the poor - in which it succeeded.

In the criticism of non-organic food, Bean sees a "middle-class, educated metropolitan audacity in telling the East End that when they shop in Asda, they should look in that tiny section at the end where a chicken costs 15 quid". Hence the following exchange in Harvest between intensifying farmer William Harrison and Agar the squire:

Agar: Mixed farming, for these little family units, was a good system you know. Feed the cereals to the livestock, use the manure to feed the fields, to grow more cereals, to feed to the animals. A cycle. There was poetry in it. The rhythm of life in accord with the seasons.

William: It's 1958. The poor want meat.

Agar: Do they? Oh dear? They don't want meat every day do they?

William: Why should they eat any less well than you?

I once asked my brother, who works for another, large-scale farmer, why he doesn't eat organic meat; he said: "Because I can't fucking afford it." So I have some sympathy. I don't think Bean is making a pro-intensive point; he is saying that the issue can't be solved by saying poor people need to make more soup. And he's right.

But this is all farm politics, and the reason Harvest is good is not its politics, but its characters. Bean is really concerned with understanding the lives of people who make what we consume; with seeing them as individuals and not a lumpen mass; with noting a culture whose values, morals and esteem contrast with the bleak, blank moral relativism that came in on the tails of the postindustrial service culture. The fact is, if you come from a British farming family in 2005, you will probably have seen friends and brothers and fathers and sisters and mothers, people you always thought invulnerable because of their work capacity, reduced to silent, looming presences whom you discover silently weeping, alone, in a kitchen, or the corner of a barn. It is the loss of sense of self and culture, not money, that really destroys people, and these things did not need to be lost to farming, just as they did not need to be lost to the mining communities before them. Politics and economics are meant to serve people, not master them. Richard Bean is one of very few modern British writers who understand that. I shall be taking my brother to see this play, if he gets finished harvesting in time.

· Harvest is at the Royal Court, London SW1,until October 1. Box office: 020-7565 5000. Richard Benson is the author of The Farm, published by Penguin, priced £15.99.